Plate girder



F. BAUER PLATE GIRDER Oct. 16, 1934.

Filed March 5, 1951 Zwenior fF/[z Bauer All Patented Oct. 16, 1934 UN 1f 1 PLATE Gianna Fritz Bauer, Stuttgart, Germany Application March 5,1931, Serial No. 520,389 In Germany March 3, 1930 5 Claims; (01; 72 -s1)My invention relates to concrete-steel hollow plate girders. It is, anobject of my invention to provide a hollow plate girder of comparativelylow weight and low initial cost. Y

To this end I build up mynovel girder from a hollow metal member ofchannel section in combination witha concrete body at the open side ofthe member. Only the flanges of the -channel-section member are embeddedin the concrete body with their outer margins only, so that the concretedoes not embed the whole channel member.

It has already been suggested in girders having a hollow steel memberand a body of concrete to provide the hollow member at the neutral zoneor at points which are not particularly important for the moment ofresistance, with the object of reducing the weight or providingfacilities for connecting other parts to the girder. Such hollowmembers, however, play a secondary part in the load capacity of thegirder. The sole weight of the girder is normally much. higher than theweight of a wooden beam of equal size While the initial cost is veryhigh onaccount of the considerable amount of material required.

According to my invention I provide a concrete steel girder in which thehollow member takes its share of the stresses. Such a girder has aboutthe same weight as a wooden girder of equal size, but its initial costis so low on account of the limited quantity of material required thatstructures including my novel girders, for in stance ceilings, are muchcheaper than other systems.

In building up a girder in accordance with my invention I provide'ahollow steel member the section of which is so determined that its soleweight and the superload on the girder are supported by the steel memberwhile the concrete body is made of such section as to prevent bucklingof the steel member.

As compared with concrete-steel girders as designed heretofore the bodyof concrete is comparatively thin, as only a small section of concreteis required for preventing deformation of the girder by thefast-sticking concrete.

My novel girder is adapted to be fabricated at the works and to beshipped to the field like any other girder or wooden beam. 7

In the drawing afiixed to this specification and forming part thereofseveral types of girders embodying my invention are illustrateddiagrammatically by way of example.

In the drawing V Fig. 1 isa section of a'girder having a tu bularmetalmember of channel section, with a concrete body at its tensionside,

Fig. 2 is a section of a girder having an inverted metal member ofchannel section, and plain metal bars in the concrete body,

Fig. 3 is a perspective illustration, partly in section, of a ceilingwith the element shown in Figs. 1 and 2 built in as girders.

Referring now to the drawing, and first to Fig. l, a. is a member ofsteel or other suitable material which is here shown as an invertedchannel section, with its open side facing the tension side of thegirder, and v is a body or block of concrete at the tension side. Theouter margins of the flanges of the channel-section member a are turnedup horizontally at as and a bottom plate 71. having upturned edges 2' issecured to the turned-up portions of the margins. m are hooks which areplaced on the turned-up portions a: for effecting a connection as willbe described with reference to Fig. 3.

Referring now to Fig. 2, the section of this element is substantiallysimilar to that illustrated in Fig. 1 but without the bottom plate It sothat it is a mere trough or channel and not a tube as in Fig. 1. Theflanges at the open side or bottom of the section a are provided withturned -up portions :0 as shown in Fig. 1, g are horizontal stirrupshaving hooks at both ends for engaging the turned-up portions andvertical stirrups n are inserted between the ties f and the turned-upportions :2: with their lower ends. The stirrups it serve the samepurpose as the hooks m as will be described with reference to Fig. 3.

My novel elements may form part of any structure and by way of example aceiling is illustrated in Fig. 3, in which p are hollow members of anysuitable section forming part of the ceiling. Girders according to myinvention are combined with the hollow members and in the presentinstance. the girder illustrated'in Fig. 2 has been shown at threepoints, slightly modified. The first girder from the left has horiwithconcrete q. Obviously, the tubular member shown in Fig. 1 might also beinserted as part of the structure shown in Fig. 3.

The edges of the steel member a and the members at its bottom, to wit,the stirrups g, the plate h (of expanded metal if desired) and the wirenetting k: are firmly anchored in the block 1) and buckling isprevented. The hooks m or the stirrups n serve as connecting linksbetween the steel member a and the concrete fillers q, Fig. 3.

If desired, the ceiling might be built up from girders placed side byside instead of pitching the girders apart and inserting the hollowmembers p between them, as shown.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

In the claims affixed to this specification no selection of anyparticular modification of the invention is intended to the exclusion ofother modifications thereof and the right to subsequently make claim toany modification not covered by these claims is expressly reserved.

I claim:

1. A plate girder comprising a hollow metal "member of channel section,and a concrete body at the open side of said member in which body theflanges of said member are embedded at their margins.

2. A plate girder comprising a hollow metal member of channel sectionwhose Web is arched and whose flanges diverge toward the opening of saidmember from its arched web, and a concrete body at the open side of saidmember in which body the flanges of said. memberare embedded at theirmargins. I

3. A plate girder comprising a hollow metal member of channel section, aconcrete body at the tension side of said member in which body theflanges of said member are embedded at their margins, and reinforcingmembers in said body.

4. A plate girder comprising a hollow metal member of channel section, aconcrete body at the tension side of said member in which body theflanges of said member are embedded at their margins, and reinforcingmembers in said body whose ends are connected to the flanges of saidmember.

5. A plate girder comprising a hollow metal member of channel section, aplate secured. to.

